1. Field of the Invention
The present invention relates to a punch holder apparatus which a punch chip is mounted to and is used for a punching process.
2. Description of Relevant Art
In the relevant art, a conventional punch holder apparatus of a burring tools contains a lot of members including a punch chip. When a thickness of a workpiece to be burred is changed by changing to another material workpiece, manually changing operation of the punch chip is required. Therefore, since the punch holder apparatus of a burring tools contains a lot of members and the structure of the punch holder apparatus is complex, the manually changing operation of the punch chip is very tedious and hard.
The present invention has been achieved with such points in view. It therefore is an object of the present invention to provide a punch holder apparatus where a punch chip can be changed so as to be mounted to and removed from a punch holder with one step and one action.
A first aspect of the present invention provides a punch holder apparatus, comprising: a punch holder formed with a punch mounting hole in a longitudinal direction of the punch holder, the punch holder further formed with an inspection hole in a direction perpendicular to the longitudinal direction of the punch holder; an engagement piece to be mounted in the inspection hole, the engagement piece being able to move in the inspection hole so as to locate on an inner circumferential surface of the punch mounting hole; a lock piece formed with a receiving allowable concave section to receive the engagement piece, the lock piece being provided so as to be capable of moving in a direction parallel to the longitudinal direction of the punch holder, the receiving allowable concave section receiving the engagement piece which is moved in the direction perpendicular to the longitudinal direction of the punch holder; and pressurizing means for pressurizing the lock piece so that an engagement piece pushing-out holding section provided to the lock piece is normally located in a position corresponding to the engagement piece.
Therefore, in order to mount a punch chip to the punch mounting hole formed in the punch holder, when the lock piece is pushed from a downward side, for example, the lock piece moves upward, for example, against an applied force of the pressurizing means, and the engagement piece pushing-out holding section provided to the lock piece slips out of the engagement piece. Then, the receiving allowable concave section comes to a position corresponding to the engagement piece so that the engagement piece is fitted into the receiving allowable concave section, and the punch chip is inserted into the punch holder. After the insertion, when the state that the lock piece is pushed is released, the engagement piece pushing-out holding section moves to the position to the engagement piece by means of the applied force of the pressurizing means so as to pressurize or press the engagement piece, and the punch chip is engaged with the punch holder.
In the case where the punch chip is removed from the punch mounting hole, when the lock piece is pushed from a downward side, for example, the lock piece moves upward, for example, against the applied force of the pressurizing means so that the engagement piece pushing-out holding section slips out of the engagement piece. In this state the punch chip is pulled, for example so that the punch chip comes out of the punch holder.
In such a manner, the punch chip is easily mounted to and removed from the punch mounting hole of the punch holder with one step.
A second aspect of the invention, as it depends from the first aspect, provides a punch holder apparatus wherein the inspection hole from which the state of the engagement piece can be checked in such a manner that the inspection hole opens to an outer circumferential surface of the punch holder.
Therefore, since the punch holder has the inspection hole, the state of the engagement piece can be easily checked from the inspection hole.
A third aspect of the invention, as it depends from the first aspect or the second aspect, provides a punch holder apparatus wherein the lock piece has a stopper section which always stops in a constant position so that the engagement piece is automatically fitted into the receiving allowable concave section.
Therefore, since the stopper section is provided to the lock piece, the stopper section always stops in a constant position, and the engagement piece is automatically fitted into the receiving allowable concave section.